1. Technical Area
The present invention concerns a device for fuel injection intended for an internal combustion engine with a wide range of speeds of revolution and with high requirements for rapid response such as, for example, the engine in a motorcycle, and a method of controlling fuel injection to such an engine.
2. Description of the Background Art
It is of the highest importance in internal combustion engines that the correct mixture of air and fuel is obtained at the correct instant in order to obtain maximal power and to achieve minimum emissions. Better control of the air/fuel mixture is obtained with the aid of fuel injection than is obtained in an engine with a carburettor. It is most common that injection occurs in the intake pipe prior to the combustion chamber. Two injectors are normally required in engines with a wide range of speeds of revolution in order to cope with the dynamic properties of the engine. The engines of motorcycles are examples of engines with advanced dynamic properties and high requirements for rapid response. The injectors have previously most often been applied in parallel and in this way received similar properties for the preparation of air/fuel. In cases where high requirements for rapid response are present, one disadvantage with existing solutions comprising double injectors working in parallel at a considerable distance from the combustion chamber is the surface film that forms when the fuel mixture is spread in the intake pipe, and the long transport time between the injection valve and the intake valve that the fuel mixture must travel. Existing solutions comprising double injectors working in parallel with a short distance to the combustion chamber have problems with poor fuel/air preparation due to the time and transport path being too short, and there are problems with the construction of these solutions.
The present invention concerns the provision of a solution that satisfies the high requirements for rapid and exact fuel supply that is required in motors with advanced dynamic properties.
The present invention concerns a method for controlling fuel injection into an internal combustion engine with advanced dynamic properties and a device for fuel injection into an internal combustion engine.
In the invention according to the present application the fuel injection to an internal combustion engine comprising an intake pipe with at least one intake valve and one or more injectors is controlled in such a manner that a first fuel injection to obtain a well prepared air/fuel mixture occurs early in the working cycle of the engine following the closure of the intake valve and a second fuel injection to obtain an optimal amount of fuel for the cycle, a process known as xe2x80x9ctransient compensationxe2x80x9d, occurs late in the working cycle before closure of the intake valve.
In order to know exactly the instant at which transient compensation is to take place, a function of the speed of revolution is used whereby the timing can be estimated and transient compensation can occur as late as possible before closure of the intake valve for the most rapid response possible. Calculations of the required amount of fuel for both stationary conditions and for transient compensation are based on the dynamic properties of the surface film. The position of the throttle is also detected for the correct calculation of the amount of fuel for transient compensation. In this way, the possibility of being able to provide compensation with the correct amount of fuel at the correct instant immediately before the valve closes is obtained. In this way, control of the amount of fuel injected is achieved, and the fuel is provided exactly when it is needed. It is difficult using traditional technology to estimate the amount of fuel that actually entered the cylinder before the valve closed and how much remained for the next cycle.